barrel extension peening via the bolt

I decided to clean my gun since I am waiting a roll in for my folding charging handle. On the feed ramp area of the barrel I see shiny metal, its been impacted via the bolt and it has lip/edge that can be felt with one's fingernail. Its the divider between the left and right feed ramp. There are no other impact points on the barrel from the bolt. The bolt face also has the same impact deformation also very small. I have taken a file to remove the burrs from both pieces. Is this normal or do I have a out of spec barrel extension and or bolt?

I check it with a M-16 field gauge (nsn #4933-00-070-7814) and it does not shut on it. The peening is right at the top most point of the divider, between the left and right feed ramps and closes to the bolt carrier(the very beginning edge of the barrel extension). So if its out of spec, its not in the headspace area.